Converter outlet lining

ABSTRACT

A converter outlet lining includes a lower layer of highly conductive material such as carbon bricks, the outer edges of which are in contact with the jacket of the converter. An upper layer of wear resistant material includes a layer of magnesia bricks on top of the carbon bricks and spaced from the jacket, and a layer of compressed or compacted granular magnesite over the inner portion of the top of the magnesia bricks. Between the magnesia bricks and the jacket and over the outer portion of the top of the magnesia bricks is a layer of compressed or compacted granular highly heat conductive material such as carbon.

United States Patent Muller 1 1 July 15, 1975 CONVERTER OUTLET LININGPrimary ExaminerGerald A. Dost M [75] Inventor Hans Her, wlesbadnGermany Attorney, Agent, or Fzrm-Wenderoth, Lmd & Ponack [73] Assignee:Didier Werke AG, Wiesbaden,

Germany [22] Filed: Feb. 6, 1974 57 ABSTRACT [21] Appl. No.: 439,862

A converter outlet lmmg includes a lower layer of u highly conductivematerial such as carbon bricks, the [30] Apphcatlo Pnomy Data outeredges of which are in contact with the jacket of Feb. 12, 1973 Germany2306858 the converter. An upper layer of wear resistant materialincludes a layer of magnesia bricks on top of the [52] US. Cl. 266/43carbon bricks and spaced from the jacket, and a layer [51] Int. Cl. C21C5/44 of compressed or compacted granular magnesite over [58] Field ofSearch 266/35, 43 the inner portion of the top of the magnesia bricks.Between the magnesia bricks and the jacket and over [56] ReferencesCited the outer portion of the top of the magnesia bricks is UMTEDSTATES PATENTS a layer of compressed or compacted granular highly 117248 7/1871 Bessemer 266/35 heat conductive material Such as Carbm663,945 12/1900 Waldburger et a1. 266/43 FOREIGN PATENTS OR APPLICATIONS5 Glam, 2 Drawmg 583,050 12/1946 United Kingdom 266/43 CONVERTER OUTLETLINING BACKGROUND OF THE INVENTION The present invention relates to animproved lining for the outlet area of converters or similarmetallurgical vessels employing therein a highly heat conductivematerial, in particular carbon.

It is well known that heavy wear occurs at the outlet of the lining of aconverter, such wear being considerably more rapid than the average wearof the remainder of the lining and being caused by a variety of reasons.The slag obtained during steel manufacture frequently possesses highiron-oxide fractions and also smaller fractions of metals, whichfractions bind intimately with the outlet lining when the slag is pouredover the edge of the outlet of the converter. There are thus formeddeposits on the outlet lining that disturb operation and whichconsequently must be removed from time to time. The lining of theconverter outlet is destroyed to a certain extent in this connection, sothat patching operations are required, making it necessary to shut downthe converter against schedule, thus resulting in additional costly downtime.

In the past, in order to prevent the above-mentioned intimate connectionbetween the slag and the lining at the converter outlet, the outletportion of the converter which contacts the slag during pouring has beenformed of carbon bricks that are highly heat conductive and possess arelatively low wetting effect in relation to slag, thereby renderingdifficult any reaction between the slag and the outlet lining.

A further cause for the premature wear of the converter outlet openinglining in relation to the remaining lining is that the gases formedduring the operation of the converter possess a relatively high fractionof CO which after-burns in the outlet of the converter, thus bringingabout an excessive thermal stressing of the lining in such area. Inorder to remove the gases from the converter as much as possible withoutafter-burning, and thus to avoid an excessive thermal stressing of theburner outlet, it has been suggested to increase the outflowing speed ofthe gases through the arrangement of a suction device. However, thisproposal has not proven entirely satisfactory.

A further proposal for improving the useful life of the outlet lining bycooling the converter outlet has likewise not proven entirelysatisfactory.

According to German published application (DT-OS) 1,433,508, the usefullife of the lining of converters may be increased by providing the partsof the lining in contact with the jacket of the converter of highly heatconductive refractory material, preferably carbon or silicon carbide, atleast in the thickness of the customary permanent lining of theconverter. According to the exemplified embodiment of this publication,the lining in the outlet area of the converter consists exclusively ofhighly heat conductive carbon and/or silicon carbide. However, suchproposal does not meet the requirements of current converter operation,since carbon cannot be employed in an oxidizing atmosphere above 400C(Harders/Kienow, page 876), and silicon carbide is not stable withrespect to basic oxides at higher temperatures. Even oxide-freemetal-melts attack SiC at l000-1200C (Harders/Kienow, page 868).

SUMMARY OF THE INVENTION The primary object of the present invention isto improve substantially and with simple means the useful life ofconverter linings in the outlet areas thereof, for the purpose ofreducing extent of wear of the outlet lining to an amount equal to thatof the remaining lining of the converter. This is achieved by employingrefractory materials of high thermal conductivity, such as carbon, onthe one hand, and materials having converter-operation-proven wearresistance, such as iron-poor sintered magnesia and sintered dolomite,on the other hand.

The invention consists basically in that the converter outlet liningincludes an upper, lO0-60O mm thick outlet lining layer ofwear-resistant material, and a lower, -400 mm thick layer of highlyheat-conductive material, the outer peripheral surface of which contactsthe metal jacket of the converter. Owing to such an arrangement of theconverter outlet lining, a sufficient amount of heat is removed throughthe highly heat conductive layer, particularly from the wear resistantlayer situated thereabove, that the slag flowing over the outlet liningduring the tipping of the converter remains only loosely attached. Thereis formed a film-type slag coating, which can be readily removed fromtime to time without damaging the lining. Additionally, the layer ofhighly heat conductive material at the inner peripheral surface of theoutlet is largely protected against the oxidizing atmosphere by thelining situated directly above and below, so that the wear of the highlyheat conductive material, which occurs in such an atmosphere, is reducedto a negligible amount. All together, the wear-resistant arrangement orcovering of the highly heat conductive layer results in a slag dischargewhich is free of problems while avoiding firm slag deposits which wouldlead to the destruction of the lining when removed, so that the desiredadaptation of the wear of the outlet lining to that of the remainder ofthe lining is achieved.

The highly heat conductive layer consists advantageosly of carbon, andthe covering layer arranged thcreabove consists advantageously ofiron-poor sintered magnesia. This embodiment has proven to beparticularly wear-resistant.

In the detailed arrangement of the outlet lining, there is providedaccording to the invention a layer of carbon bricks, on top of whichthere is arranged a layer of sintered magnesia bricks having a length ofone third to two thirds of the width of the lining. The inner ends ofthe magnesia bricks are flush with the outlet opening. Above the layerof magnesia bricks is a layer of compressed or compacted granularmagnesite extending from the outlet opening to the outlet flange of theconverter. Peripherally outwardly of the magnesite material is a layerof compressed or compacted granular carbon material extending from themagnesite layer to the metal jacket of the converter. By a relativeadjustment of the amount of highly heat conductive material behind themagnesite material, it is possible to adapt the heat removalcapabilities to the operational conditions of the converter, and tothereby obtain a desired amount of outlet lining wear uniform with thewear of the remaining lining of the converter.

If the premature wear of the outlet lining occurs always in certainareas, a further proposal of the invention provides for the arrangementof highly heat conductive material only at the positions of prematurewear, rather than through the entire lining of the outlet of theconverter.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred exemplified embodiment ofthe invention will be described in detail with reference to theaccompanying drawings.

FIG. 1 is a longitudinal section through the wall of a converter in thearea of the outlet thereof; and

FIG. 2 is a sectional plan view taken along lines II-II in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. 1, the jacket 1 of aconverter has supported thereon a double flange 4, defining an outlet 2,by means of brackets 3. The main converter lining 5 consists of apermanent lining 5', an intermediate layer 5" of compressed or compactedgranular material and a wear lining 5" of magnesite and/or dolomitebricks. The lining 5 has on top thereof an outlet lining including alower layer of carbon bricks 6 of a thickness of for instance 200 mm.The layer of bricks 6 is positioned 440 mm below the top of opening 2and extends over the entire width of the lining, and the outer faces 7of bricks 6 are in full and direct contact with jacket 1. A layer ofmagnesite bricks 8 is placed flush with the inner face of the outletlining on top of the layer of carbon bricks 6. The magnesite bricks 8are approximately half as long as carbon bricks 6. The free spaceperipherally outwardly of the magnesite bricks and below the converterflange 4 is filled with a layer 9 of compressed or compacted granularcarbon material in such a manner to enclose the outer ends of themagnesite bricks 8 facing jacket 1. Over the remaining top surface ofmagnesite bricks 8 and extending peripherally inwardly of layer 9, thereis positioned layer 10 of compressed or compacted granular magnesitematerial which defines the outlet of the converter with an inclinedannular surface 11 extending upwardly and outwardly from the inner upperedge of magnesite bricks 8 to the inner upper edge of converter flange4.

It will be apparent that by a suitable relative adjustment of the amountof the carbon material with respect to the covering magnesite material,the heat removal can be set to the desired operational conditions of aspecific converter, and the wear of the outlet lining can thus beadapted to be equal to the wear of the remainder of the converterlining.

I claim:

1. An outlet lining for the outlet area of a metallurgical vessel, suchas a converter, such vessel including a main lining, a metal jacketsurrounding said main lining, and an outlet flange defining the outletopening of said vessel, said outlet lining comprising:

a lower layer of highly heat conductive material, the outer surface ofwhich is in direct contact with said metal jacket of said converter,said lower layer comprising layer of carbon bricks on top of said mainlining, the innermost ends of which form a portion of said outlet andthe outermost ends of which are in contact with said jacket; and

positioned on top of said lower layer, an upper layer of wear-resistantmaterial, said upper layer comprising a layer of sintered magnesiabricks on top of said layer of carbon bricks, the length of saidmagnesia bricks being from one-third to two-thirds the length of saidcarbon bricks, the innermost ends of said magnesia bricks forming aportion of said outlet, there being a space between the outermost endsof said magnesia bricks and said jacket, and a layer of compressedgranular magnesite material positioned over a portion of the top of saidmagnesia bricks, the inner surface of said layer of magnesite materialforming a portion of said outlet.

2. An outlet lining as claimed in claim 1, wherein said lower layer hasa thickness of from -400 mm, and said upper layer has a thickness offrom 100-600 mm.

3. An outlet lining as claimed in claim 1, wherein said inner surface ofsaid layer of magnesite material is inclined upwardly and outwardly fromthe inner upper edge of said magnesia bricks to an inner upper edge ofsaid outlet flange.

4. An outlet lining as claimed in claim 3, further comprising a layer ofcompressed grannular highly heat conductive material positioned in saidspace between said outermost ends of said magnesia bricks and saidjacket and over a portion of the top of said magnesia bricks, theoutermost edge of said layer of compressed granular highly heatconductive material being in contact with said jacket.

5. An outlet lining as claimed in claim 4, wherein said compressedgranular highly heat conductive material comprises carbon.

1. AN OUTLET LINING FOR THE OUTLET AREA OF A METALLURGICAL VESSEL, SUCHAS A CONVERTER, SUCH VESSSEL INCLUDING A MAIN LINING, A METAL JACKETSURROUNDING SAID MAIN LINING, AND A OUTLET FLANGE DEFINING THE OUTLETOPENING OF SAID VESSEL, SAID OUTLET LINING COMPRISING: A LOWER LAYER OFHIGHLY HEAT CONDUCTIVE MATERIAL, THE OUTER SURFACE OF WHICH IS IN DIRECTCONTACT WITH SAID METAL JACKET OF SAID CONVERTER, SAID LOWER LAYERCOMPRISING LAYER OF CARBON BRICKS ON TOP OF SAID MAIN LINING, THEINNERMOST ENDS OF WHICH FORM A PORTION OF SAID OUTLET AND THE OUTERMOSTENDS OF WHICH ARE IN CONTACT WITH SAID JACKET, AND POSITIONED ON TOP OFSAID LOWER LAYER, AN UPPER LAYER OF WEAR-RESISTANT MATERIAL SAID UPPERLAYER COMPRISING A LAYER OF SINTERED MGNESIA BRICKS ON TOP OF SAID LAYEROF CARBON BRICKS, THE LENGTH OF SAID MAGNESIA BRICKS BEING FROMONE-THIRD TO TWO-THIRDS THE LENGTH OF SAID CARBON BRICKS, THE INNERMOSTENDS OF SAID MAGNESIA BRICKS FORMING A PORTION OF SAID OUTLET, THEREBEING A SPACE BETWEEN THE OUTERMOST ENDS OF SAID MAGNESIA BRICKS ANDSAID JACKET, AND A LAYER OF COMPRESSED GRANULAR MAGNESITE MATERIALPOSITIONED OVER A PORTION OF THE TOP OF SAID MAGNESIA BRICKS, THE INNERSURFACE OF SAID LAYER OF MAGNESITE MATERIAL FORMING A PORTION OF SAIDOUTLET.
 2. An outlet lining as claimed in claim 1, wherein said lowerlayer has a thickness of from 100-400 mm, and said upper layer has athickness of from 100-600 mm.
 3. An outlet lining as claimed in claim 1,wherein said inner surface of said layer of magnesite material isinclined upwardly and outwardly from the inner upper edge of saidmagnesia bricks to an inner upper edge of said outlet flange.
 4. Anoutlet lining as claimed in claim 3, further comprising a layeR ofcompressed grannular highly heat conductive material positioned in saidspace between said outermost ends of said magnesia bricks and saidjacket and over a portion of the top of said magnesia bricks, theoutermost edge of said layer of compressed granular highly heatconductive material being in contact with said jacket.
 5. An outletlining as claimed in claim 4, wherein said compressed granular highlyheat conductive material comprises carbon.